Surface texture and groove designs for sliding contacts

Abstract

A sliding contact assembly includes a first surface and a second surface. The second surface of the sliding contact assembly is configured to slide over the first surface, and at least a portion of the second surface contacts the first surface to form at an interface between the first surface and the second surface. The sliding contact assembly also includes a plurality of textures on the portion of the second surface that contacts the first surface. A density of the plurality of textures is not uniform over the portion of the second surface that contacts the first surface. The sliding contact assembly can include apex seal to housing interfaces in rotary engines, roller to roller interfaces, roller to housing interfaces, bearing to surface interfaces, etc.

What is claimed is: 
     
         1 . A sliding contact assembly comprising:
 a first surface;   a second surface that is configured to slide over the first surface, wherein at least a portion of the second surface contacts the first surface to form at an interface between the first surface and the second surface; and   a plurality of textures on the portion of the second surface that contacts the first surface, wherein a density of the plurality of textures is not uniform over the portion of the second surface that contacts the first surface.   
     
     
         2 . The sliding contact assembly of  claim 1 , wherein the plurality of textures are disposed along a centerline of the portion of the second surface that contacts the first surface. 
     
     
         3 . The sliding contact assembly of  claim 1 , wherein the plurality of textures are disposed along a leading edge of the portion of the second surface that contacts the first surface. 
     
     
         4 . The sliding contact assembly of  claim 1 , wherein a distance between centers of adjacent textures is a Hertz contact radius. 
     
     
         5 . The sliding contact assembly of  claim 1 , wherein the plurality of textures comprise indentations. 
     
     
         6 . The sliding contact assembly of  claim 5 , wherein the indentations have an R-type depth profile. 
     
     
         7 . The sliding contact assembly of  claim 5 , wherein the indentations have a T3-type depth profile. 
     
     
         8 . The sliding contact assembly of  claim 5 , wherein the indentations have a depth in a range from 0.1 μm to 7 μm. 
     
     
         9 . The sliding contact assembly of  claim 5 , wherein each of the indentations has a width that is less than or equal to a Hertz contact radius. 
     
     
         10 . The sliding contact assembly of  claim 1 , wherein the textures are square or oval in shape. 
     
     
         11 . The sliding contact assembly of  claim 1 , wherein the textures are configured to reduce friction at the interface. 
     
     
         12 . The sliding contact assembly of  claim 1 , wherein the first surface comprises a housing, and wherein the housing includes a pair of parallel grooves to prevent leakage at the interface. 
     
     
         13 . The sliding contact assembly of  claim 12 , wherein the parallel grooves have a depth of at least 5 microns. 
     
     
         14 . The sliding contact assembly of  claim 12 , wherein the parallel grooves have a T3-type depth profile. 
     
     
         15 . The sliding contact assembly of  claim 12 , wherein the parallel grooves have an R-type depth profile. 
     
     
         16 . The sliding contact assembly of  claim 12 , wherein the parallel grooves run along a rotational direction of the second surface. 
     
     
         17 . A rotary engine comprising:
 a housing having an interior surface that defines a rotor cavity;   a rotor mounted in the rotor cavity, wherein the rotor includes at least one apex;   an apex seal at the at least one apex of the rotor, wherein the apex seal includes a sealing surface that forms an interface between the rotor and the interior surface of the housing;   wherein the rotor is configured such that the sealing surface of the apex seal is in sealing contact with at least one area of the interior surface of the housing as the rotor rotates in the rotor cavity; and   wherein the interior surface of the housing defines a pair of parallel grooves formed within the at least one area of the interior surface of the housing such that the parallel grooves run in a rotational direction of the rotor.   
     
     
         18 . The rotary engine of  claim 17 , wherein the parallel grooves have an R-type depth profile or a T3-type depth profile. 
     
     
         19 . The rotary engine of  claim 17 , wherein a sealing surface of the apex seal includes a plurality of textures, and further wherein a density of the plurality of textures is not uniform over the sealing surface of the apex seal. 
     
     
         20 . The rotary engine of  claim 19 , wherein a distance between centers of adjacent textures is a Hertz contact radius.